Resummation of Large Endpoint Corrections to Color-Octet J/psi Photoproduction

Journal Article · Thu Jul 27 04:00:00 EDT 2006

OSTI ID:887317

Fleming, Sean; Leibovich, Adam K; Mehen, Thomas

An unresolved problem in J/{psi} phenomenology is a systematic understanding of the differential photoproduction cross section, d{sigma}/dz [{gamma} + p {yields} J/{psi} + X], where z = E{sub {psi}}/E{sub {gamma}} in the proton rest frame. In the non-relativistic QCD (NRQCD) factorization formalism, fixed-order perturbative calculations of color-octet mechanisms suffer from large perturbative and nonperturbative corrections that grow rapidly in the endpoint region, z {yields} 1. In this paper, NRQCD and soft collinear effective theory are combined to resum these large corrections to the color-octet photoproduction cross section. We derive a factorization theorem for the endpoint differential cross section involving the parton distribution function and the color-octet J/{psi} shape functions. A one loop matching calculation explicitly confirms our factorization theorem at next-to-leading order. Large perturbative corrections are resummed using the renormalization group. The calculation of the color-octet contribution to d{sigma}/dz is in qualitative agreement with data. Quantitative tests of the universality of color-octet matrix elements require improved knowledge of shape functions entering these calculations as well as resummation of the color-singlet contribution which accounts for much of the total cross section and also peaks near the endpoint.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA
• Sponsoring Organization: USDOE - Office of Energy Research (ER)
• DOE Contract Number: AC05-84ER40150
• OSTI ID: 887317
• Report Number(s): JLAB-THY-06-499; DOE/ER/40150-3992; hep-ph/0607121
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
DISTRIBUTION FUNCTIONS
FACTORIZATION
MATRIX ELEMENTS
PHOTOPRODUCTION
PROTONS
QUANTUM CHROMODYNAMICS
RENORMALIZATION
SHAPE
TOTAL CROSS SECTIONS